Mystery Child
by LazyFae
Summary: When bodies started showing up in London, even Sherlock was stumped. But then one turns up alive; a secretive child with an impossible past. In trying to crack open the boy, Sherlock is confronted with his own inability to open himself to others. It's a battle of stubbornness between the two. John's just amused at it all for once. AU! Post season 2
1. Chapter 1

Disclaimer: I own nothing but the general plot and OCs

 **IMPORTANT AND ONLY WARNING:**

This is not going to be an extremely dark story but nor is it all light hearted and fluffy. I have little clue where this is going to go yet and thus can't say for certain what it'll contain.

I will say this: If it can be perceived for a person to do something/have something happen to them it may well be in this story

 **This may or may not include:** **Pairings of all genders and ages. Non consensual and dubious consensual content. Violence. Abuse. Character deaths. Angst. Plot holes.** **discrimination and prejudice. excessive fluffiness and icky romance. Much more.**

That's not to say it will definitely have all this in it, however I'm not too interested in skipping or brushing over something because it's uncomfortable if it's relevant to the plot. If it's included I will try to do the topic genuine credit and treat it with the seriousness it deserves as long as it's not a parody/comedy or a character being politically incorrect.

 **The plot and characters do not necessarily reflect my own views** and so if you are horribly offended by what's coming out a characters mouth/mind or their actions, that's fine.

* * *

 **Info you might want to know about this story:**

I don't think this is going to be Johnlock but I may change my mind. Also this is only sort of parentlock but also not really.

This doc has been sitting in my files for ages now, and I haven't uploaded it unless I was going to commit to regular updates, but I figured what the hell, I will never get round to updating it unless I upload.

Having said that, expect incredibly sporadic updates. I have a bunch of fics which are in the same state in my files and I will pick up and drop them again as time goes on, or favour one to the exclusion of the others for a while before I take a long break from it.

no beta btw

Finally let me know what works for you, what doesn't, or just what you think in general! As well as anything you'd like to see in the fic going forward.

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 **Chapter 1**

Clenching and unclenching his fist every five seconds in an admirable attempt to maintain a calm facade, John Watson debated whether eating was really necessary for the next few days, or whether he could get away with giving shopping up for a bad job and storming out (in a dignified manner of course). He grit his jaw so that he didn't end up snapping out insults in a truly impressive Sherlock style to the woman in front of him and probably being banned for life from the store. Thanks to Sherlock they were already banned from a total of five restaurants and three food stores in London, a number which would have been much larger if John weren't so good at damage control by now. Of course Sherlock's fame often gave him some leeway ever since his reputation became that of an eccentric genius who could come back from the dead.

Just as John was seconds away from giving up, his phone dinged with a text from Sherlock.

 **Meet me at St. Thomas' Hospital. By the river -SH**

almost immediately followed by another text.

 **Another one. This time alive -SH**

John's breath caught in his throat, and he eagerly abandoned the food in order to meet Sherlock.

* * *

"There you are John. What took you so long." Sherlock barely glanced at John as he swept into the building, an almost hungry expression on his face, in his haste to hear about the newest development in the case that had everyone both baffled and horrified. Except Sherlock, who was just increasingly short tempered at the dead ends he kept coming across. Every unsolved case was like a blow to his over sized pride and this one in particular was both intriguing and frustrating; a case which should be teeming with fresh evidence and facts to observe that hadn't been tampered with and lost over time.

John huffed, "I was shopping for food, remember."

"Ugh, dull," Sherlock dismissed with a wave of his hand. They continued to hurry down the corridors until they met Lestrade who had been waiting for them.

"What do we have," Sherlock demanded, resisting the urge to clap his hands in excitement since he was fairly sure that it would be viewed as 'a bit not good'. Lestrade filled them in as they walked.

"Unlike the other victims, the boy wasn't found in the Farmer's Club building. The new security cameras blacked out for a two and a half minutes at 3.30am like before but this time there was no body when they turned back on. He turned up at 7am at a hospital, after he was found trying to break into the Farmer's Club building. The police got there quickly thinking they might have caught the killer but before they got to question him he passed out. The kid woke up about ten minutes ago but he was still disorientated when I left and I haven't been able to get a word out of him. You don't think... he's the helping the killer do you? It's just a bit too much to be a coincidence that the cameras blacked out again last night and this morning he was trying to break in."

Lestrade glanced at the silent Sherlock with a troubled expression, a serial murder case like this was wearing down the spirit of even the most detached officers on the case, and with no leads on top of that Greg was just praying that Sherlock could give them what they needed to catch the sick bastard doing this. He hesitated, disturbed by what he was about to say, before forging on determinedly.

"That's not all though. All of the victims have been 18 and 19 year olds, without a scratch on them. This kid's young- I'd guess somewhere around 6 or 7. Also he's covered in cuts and bruises. Nothing life threatening mind, all fairly superficial, but it's still different from what we've had so far."

Sherlock peered sharply at the D.I, "does he have the same kind of scars on him that the others do?" Greg nodded, before looking at his notepad.

"It looks like it. He has a jagged scar on his forehead sort of in the shape of an 's', around his neck from being burned by a necklace, and he's had the words 'I must not tell lies' carved into his right hand. Those are the most notable ones."

"Christ," John muttered with a grimace. Sherlock, on the other hand looked excited.

"Interesting. I must not tell lies, and mudblood. Clearly a derogatory term. But she didn't have any viruses or toxins in her blood, and her ancestry showed no leads. Someone is clearly punishing these individuals but whether it's the killers or not has yet to be seen."

Lestrade looked confused, "wait. Killers? There's more than one? And you think this kid's a victim?"

Sherlock made an impatient sound and looked at The D.I as though he were being purposely stupid, "of course there's more than one killer. The two adolescent males both had a mass of over 68 kilograms. And yet were dumped there quickly and effectively with no one any the wiser. Not to mention the fact that the second male was dumped alongside a female at the same time. How do you expect one killer to have done that in under three minutes without being noticed or leaving a trace of themselves behind? This child is clearly both incapable of transporting the bodies, and his attempt at entering the building was messy, leading to his capture. He might be a petty criminal at the wrong place at the wrong time but it's doubtful. Especially considering his scars. For God's sake Lestrade at least attempt to use that pathetically simple brain lest I drown in the sea of ineptitude that is Scotland Yard's finest."

"Alright Sherlock just... try to be considerate yeah? The guys working on this case are already touchy about the whole thing. I don't want you saying something and getting them all worked up." Lestrade insisted, his resigned expression showing how he expected his request to be unfulfilled. Sherlock had been particularly barbed with his insults as the case had dragged on with no end in sight.

As they approached a door being guarded by Donavon, Sherlock frowned, "what are you talking about? I'm always considerate," he flashed an unconvincing grin at the D.I and entered the room, followed by a mildly exasperated Dr. Watson.

In the hospital bed John could see that this boy had various bruise and cuts all over him. He was skinny and pale, with black hair that resembled the youngest Holmes' with slightly less curl. It disturbed him at how easy it was to imagine him as a young, battered Sherlock.

The man himself was stood over the boy, his eyes flicking over his face and body, seeing clues and details that no one else would pick up. Whatever he saw both confused and fascinated him. The boy looked up at Sherlock becoming more wary and visibly distressed as the seconds dragged on with the tall intimidating stranger looming over him silently. John rolled his eyes at Sherlock's non existent bad side manner and approached the boy, who's eyes immediately flicked over to the doctor the moment he moved.

"Hello," he smiled kindly at the boy, deciding he would deal with this as he would with his more frightened patients, and resolutely ignoring the fact that the child's gaze was more piercing and intrusive than even Sherlock's, "my name's Doctor Watson, but you can call me John. Can you tell me your name young man?"

Sherlock rolled his eyes at the doctor, "honestly John he's a child, not a total idiot, you needn't talk to him like he'll self destruct any moment."

John suppressed the urge to scowl at Sherlock. For all his grating and highly anti social behaviours, Sherlock was surprisingly good at dealing with most children, providing they weren't in a highly emotional or sensitive state, which John worried was the case with this boy. It was something to do with the way he spoke to them as though they were adults, but with far less disdain, that made them either respectful and a tad intimidated, or eager to prove their worth to him.

When asked, Sherlock had mentioned that children were often far more observant than their adult counterparts, far more open minded and also far more accepting of Sherlock's oddities, which made them on the whole more bearable to deal with provided one could get past their painfully limited vocabulary and predictable questions.

"My name's Harry," the boy replied hesitantly, looking back at Sherlock with a mixture of confusion and amusement, "what's your name?"

"Sherlock Holmes," he replied succinctly. Sherlock noticed that Harry didn't so much as blink at his odd name, like people (especially children) often did, "what's your surname? We'll need to get in contact with your parents. I'm sure they'll be relieved you're alright."

Harry's eyes shuttered immediately, and he looked steadily back at Sherlock, "my parents are dead, sir."

Sherlock's features flashed with momentary triumph, and John resisted the urge to snap at Sherlock for forcing the kid to admit something he clearly already knew and just wanted confirmed.

"As I suspected. You're also reluctant to divulge your surname, so you don't want to be found. No doubt your Aunt and Uncle are abusive and neglectful, which, compared to the overindulgent attitude they give to your cousin makes you desperate not to go back. Your parents died suddenly and likely violently some time ago when you were young, where you got that scar," Sherlock pointed the scar on his forehead which Harry had been attempting to cover with his fringe, "you knew the other dead victims personally, since you were their charge of sorts.

"You've all been through extremely trying times together and have saved each other's lives, likely more than once, which has formed a close camaraderie between you all. You've known each other for years and belonged to some sort of club or society together, which doesn't strongly involve their parents. You've spent the last two months with them in a stone cell, which you escaped from once and fought against your attackers, leaving you with those bruises and cuts. An admirable attempt, but really, as a child you could have saved yourself the trouble of trying to overpower two adults at the same time."

There was a stunned silence, during which John covered his face in despair. Goddam it Sherlock! He mentally growled. They'd never get near the kid to get more formation from him again. Harry just looked like his brain had shorted out as he stared at Sherlock.

"Well? Did I get it all right? I'm right aren't I."

Harry swallowed, and his eyebrow furrowed slightly as he got himself under control. He eyed Sherlock warily for a moment and something flashed across his face that was too fast for either man to identify, before it was gone. Sherlock watched, captivated as Harry quickly blanked his expression successfully enough that even he couldn't tell what the boy was thinking or feeling.

"They weren't in charge of looking after me. We looked after each other. We were equals," Harry murmured, slightly defensively. Sherlock pursed his lips in irritation ('there's always something.')

John was less concerned about the fact that Sherlock was unsurprisingly correct in his deductions, and more worried about Harry's emotional response at having the fact that he was abused, his parents were dead, and so were his friends blurted out by an unfeeling idiot stranger. But the boy's expression carefully concealed any of his inner feelings to give John a clue.

"Aren't you going to ask how it's done? Everyone else under 14 always asked how it was done," Sherlock pouted, disappointed at Harry's lack of curiosity.

Harry just looked slightly confused for a moment before he gave Sherlock a look. John laughed suddenly, which caused Sherlock to spin around and face him.

"What?" He snapped.

"He's giving you the look that you give me. I never expected the look to be directed at you," John laughed again at the irony of a young child being the one to give Sherlock the look.

"What look?" Sherlock demanded angrily.

"The we-both-know-what's-going-on-here look, when only one person does." Sherlock huffed and crossed his arms defensively.

"I don't understand. He read my mind... right?" The innocently perplexed expression on Harry's face immediately served to endear him to John. Sherlock scoffed as though it was unreasonable for a child his age to leap to that conclusion having had facts he shouldn't know about Harry spouted out with such certainty.

"Of course not, don't be an idiot."

"Sherlock!"

"I'm just trying to help him John. How will he learn to use his brain to its best capacity if no one tells him when he's being stupid. No, I observed the evidence in front of me, and deduced this about you from what I observed."

Harry hesitated, frowning, "I don't understand."

Sherlock muttered something that sounded like 'of course you don't' before he straightened his spine.

"Most people wander through life happily blinkered to everything around them and not using their minuscule little brains for anything of importance. Any other witless fool would walk in here and only see a young child who's been a bit bashed about, with a few odd scars that leave concerns about abuse. They would see but they would not observe like I do.

"The clothes you were wearing, hand me downs, male, far too large. Perhaps your family is just poor, but the original clothes were expensive and all from the same shops and the same size, so they were given to you from the same person who clearly didn't appreciate them and ate excessively. That coupled with your malnutrition and the old burn scars on your arm from a hot frying pan when you were far too young to be cooking by the angle of your arms at the time leads me believe it was neglect at the least and abuse at the worst. Not both your birth parents as it was unlikely- though not impossible- they'd treat one child so much better than the other for no reason. You confirmed this when you said they were dead. Close family then, Aunt, Uncle, and male cousin is the most probable.

"You attempted to cover your scar as soon as I mentioned your parents' deaths, so you associate it with their demise, you were there at the time, you saw it happen, but it didn't cause you undue sadness to think about it and the scar is old, so it happened some time ago, when you were too young to remember clearly. As for your friends y-"

The door opened and Lestrade peered in, checking to make sure Sherlock hadn't traumatised the kid.

"I can give you five more minutes Sherlock and then you need to leave."

Sherlock sneered and opened his mouth to obviously make an acerbic comment about the state of the police force, but a warning look from John stopped him. Instead he merely nodded once, looking extremely

put out at having had his monologue interrupted.

"How did you know about the... Society bit?" Harry asked cautiously, clearly impressed. Sherlock puffed himself up a bit.

"Obvious of course. Both you and other victims have handled owls, parchment, and quills on a regular basis. All highly unusual and doesn't correlate to any profession, the fact that you've all done it points to an old tradition. A tradition that belongs to either a club or society, since you've all been raised by different people in different manners I deduced it was one in which none of you rely on your families too much, most likely because they aren't involved in it but possibly because the society works by separating children and parents for long stretches of time."

Harry looked suitably gobsmacked, and nodded his head dumbly, "wow. You're a genius. You're even smarter than Hermione...used to be."

"Hermione?" John ventured. The boy looked downcast, and bit his lip harshly as he swallowed heavily to reign in his tears. Sherlock's expression softened slightly.

"Ah. The girl with bushy hair, and rough skin from paper cuts on her fingers borne from excessively reading books."

Harry nodded, avoiding eye contact. Sherlock sighed, and turned to John for help. They needed to ask him some questions which they couldn't do if he was too upset to talk.

"Harry. We're trying to catch the people who did this. At the moment you're the only one who can help us. Can you try answering our questions?" John gently asked. Harry was silent for a long moment before he took a deep shuddering breath and nodded.

Somehow managing to make the action dramatic, Sherlock sat in the seat next to the bed and leaned forward, eager to have the puzzle finally make sense.

"What does mudblood mean? Why was it carved into Hermione's skin?"

John rolled his eyes at Sherlock's insensitively excited tone.

Harry took another deep breath to prep himself, "the... Society we belonged to is pretty old. They're also really careful with who they let in. They like to keep it among the old families. Hermione was like... New blood. Some people didn't like that. They wanted her and those like her dead. None of us liked that. We all wanted the new members to be welcome. They're just as good as any of us just because they haven't been brought up knowing about it like everyone else and they don't have 'pure blood'. They called her mudblood because she had 'dirty blood'."

Sherlock looked absolutely beguiled by this information. He wanted to sit there and question Harry about this society for much longer, but time was of the essence and he had a case to solve so he reluctantly put his curiosity on the back burner. But an extremely insular secret society would certainly explain why they couldn't find the victims on any database.

"Were they the ones who carved those words into your hand? For telling so called lies about people like your friend Hermione?"

Sherlock could see Harry was heavily modifying his answers, and he was determined to spend more time around the boy so he could find out more about him. He was intelligent for an eight year old.

"Sort of. I said some stuff about the man who was trying to convince people to get rid of muggleborns -first generation members. People stopped listening to him when I was little, and I was trying to tell people... I was trying to tell them he was going to start making trouble again but they didn't believe me. They were scared, and because they were scared they got angry. They got angry with me and my friends. We were right, and in end people believed us, but by then it was too late."

John grimaced in disgust, sometimes he could see why Sherlock got so fed up with people's stupidity. It was vile to punish a child to that extent to cover up their own fears, and no doubt make them feel like they had some semblance of control. By the look of distaste on Sherlock's face he was of the same mind.

"This society... Racist... Barbaric... Ignorant," he muttered.

Sherlock's eyes flickered over to John briefly and he hummed in agreement, a small amount of amusement at John's indignation on Harry's behalf.

"The people who were responsible for killing your friends, what can you tell me about them."

Harry's face immediately blanked again, he was silent for a long moment and his gaze seemed to see right through the men. Sherlock held perfectly still as Harry's vivid green eyes bore through his own and into his mind. He felt as though his character were being intimately judged.

When Harry finally looked down at his fingers lying on top of the covers, both John and Sherlock let go of a breath neither had realised they were holding.

"The people responsible are dead," he admitted quietly, an edge in his voice that dared them to ask how the killers died.

But neither did. They both understood what Harry wasn't telling them. They glanced at each other and agreed not to question him further down that line.

"How did you find yourself at the building where the police got to you?" John asked softly.

Harry smiled a bitter pained smile. It wasn't an expression John had ever seen on such a young person who was already so world weary.

"I didn't have anything else to go off of. I'd escaped them all. They all think I've died and I wanted to keep it that way. I don't care if most of them would thank me for... . I didn't want anything to do with them. But I wanted to find out what happened to my friends. They got taken from their cells and then I just never saw them again. All I had to go off of was that building. I had to start somewhere."

It briefly occurred to Sherlock that the first time the boy had received confirmation of his friends' deaths had been when he'd inadvertently informed him through his deductions. Harry hadn't even shown any grief or realisation. Fascinating. He had also just as good as admitted to killing an indeterminate number people and he showed no outward strain or mental struggle.

Although he had deduced that he and his friends had been through some very turbulent times so perhaps this wasn't the first time he had had to kill someone. In fact Sherlock would be surprised if it was.

"Why did they target you and your friends specifically? You can't have been the only person who disagreed with the discrimination, and you can't have been the only group of friends that included a.. Muggleborn."

He suspected Lestrade would enter any second now, having given them twice the amount of time he said he was going to, and he desperately wanted to observe this child for as long as he could. There was just something utterly compelling about him and Sherlock had the feeling that they had only just scratched the surface on the mystery of this person.

Perhaps if he hacked into any information from his therapist that he would undoubtedly be set up with. He could get hold of the child every few weeks in between cases too to talk to him and get him to open up slowly.

Harry heaved a sigh and looked resigned, "the man who was encouraging the discrimination was responsible for my parents deaths. It weakened him. His support group crumbled. It made me famous and it meant he saw me as the opposition when he started up again. Everyone did."

John felt sorry for child who had clearly been dragged into a very dangerous adult situation and thrown into the deep end, then not only expected to be able to swim but keep everyone else afloat too.

Sherlock on the other hand was looking at Harry's scar and seeing it in a new light, having observed how Harry tried to keep it hidden. It was clearly what was most commonly used to identify him by if he was well known and it was also a symbol of anti-discrimination. No wonder they tried to kill him and any who openly supported him. As long as he lived he would be used to give them hope.

"They saved you for last because you were the most important. You were pressured into to be their hope and you tried to live up to their expectations too despite the fact that they had punished you barbarically for trying at first. They killed your friends because they were a reminder of you and what you fought for. They would be capable of spreading dissent even after you were gone." Sherlock suddenly held a lot more respect for the child who was barely a child in front of him. Not that he made it known of course, he looked as impassive as ever.

"They were punished for sticking up for me," the boy's gentle voice wavered for a moment and the tears that had been building up as Sherlock spoke made their way silently down his face. The boy took a deep shuddering breath and tried to suppress his tears with partial success.

"I told them not to." He face practically pleaded for Sherlock to believe him, and forgive him.

Curious. He had remarkable control over his emotions. He viewed himself to be just as responsible as the killers for the death of his friends. He was the leader amongst them. Of course he had impressive emotional control to be an eight year old leader during what was looking like an underground war amongst adults. Obvious.

"It wasn't your fault," John smiled sadly, "it was their right to choose to fight or stay safe and they chose to stand by your side. I suspect they would have fought with or without you. You were just there to take the fall."

Ah, ever faithful John and his ability to understand sentiment. Sherlock suspected Harry was more likely to be rational rather than emotional now if he hadn't been like it before, but he was clearly vulnerable around the issue of his responsibility for his friends. As an ex-soldier John would be better equipped to handle that.

"Besides, now you don't have to suffer too much guilt about those you left behind to mourn since your closest friends are dead. In fact if you're allowing yourself to become a martyr it would be better that those who knew your flaws and humanity well are dead so its easier for your image to become inhuman and therefore timeless, thus discouraging that particular discrimination more effectively."

John sighed in despair, "not helpful Sherlock."

Harry looked both amused and disturbed, "er... Thanks. I guess."

"Although in my opinion your time would far better be served teaching those fools not to idly stand by and allow children do their battles for them, rather than dying so they can worship your memory in order to avoid looking at their own transgressions."

Harry shook his head, "they're just sheep. They always follow whoever has the loudest voice at the time. Mine wasn't strong enough earlier on when more people would have stood by me."

Sherlock snorted. Typical. Even in a society filled with severely elitist members there are mindless masses blindly following whoever promises the least work.

"Can I ask you some questions now, sir?" Sherlock nodded once.

"Provided of course you make them intelligent questions and not the pathetically asinine queries that most of the populace spew out. And call me Sherlock." Harry's lips twitched in suppressed humour, and Sherlock smirked.

"What's going to happen to me now?" Harry asked, anxiety lurking in the back of his eyes whilst he strove for nonchalance.

"The police will have some questions for you. No doubt you'll act much more innocent and oblivious in order to avoid being forced to give names and addresses and John and I will support you in the claim of self defence in the case of the killers, since you have the injuries to sustain it... And then you'll most likely be taken to a foster home if they can't find any next of kin for you, which I doubt they will since you won't be going back to your abusive aunt and uncle if we find them.

"It's unlikely that you'll be adopted, since you're eight years old and most parents want a baby or toddler that will view them as mothers and fathers. You'll be pushed through the system whilst everyone around you tries to make you act normal," Sherlock sneered the word, "and by the time you reach adulthood, if you haven't managed to get yourself into a lot of trouble which I have no doubt you would, you'd be resentful of everyone and wish you were back to living among the people who happily sacrificed you just so you could be a semblance of your real self, surrounded by people who would allow you to act like the soldier I can tell you are."

The fear that had been lurking in the background came rushing to the front, along with panic and dread. Sherlock wondered if perhaps he should have softened his words or lied. But he decided that if your future prospects were mostly miserable you ought to know about it. However that didn't mean he wanted to have to deal with an eight year old soldier with nothing to lose, barely out of the killing mindset and having a panic attack.

"Sherlock!" John hissed furiously.

"What? Not good?" Sherlock inquired, eyeing Harry cautiously.

"Bit not good yeah," John snapped, trying to refrain from shouting semi-successfully.

Lestrade, who had all been impatiently waiting outside the room trying to distract Donavon from the fact that he had allowed Sherlock access to a child, finally relented when they heard a raised voice and burst inside.

Harry's breathing had increased to the point of hyperventilating and he had his head buried in his hands.

"I suspect he has a fear of foster care and possibly orphanages. I didn't foresee that," Sherlock explained calmly.

"I told you the freak shouldn't be allowed anywhere near kids! Probably traumatised him even more."

"Yes alright! Alright Donavon, thank you but that isn't helping. Sherlock! I told you to be considerate! What did you say to upset him," Lestrade gritted his teeth in frustration.

Sherlock answered distractedly, noting Harry's reaction to what Donavon had said carefully, "I merely informed him that he was going to be placed and grow up in the foster system, with people who would try to crush whatever makes him unique."

All three groaned, "you told him that?! Of course that upset him!" Greg restrained himself from shouting.

"Is that not what's going to happen to him if next of kin can't be found?" He defended himself.

"Well yes but that's not the point. You can't just go around blurting that kind of life altering information out Sherlock," John rubbed his forehead in annoyance.

"Don't expect the freak to be sensitive or, God forbid, compassionate. He's a psychopath. He's completely incapable," Donavon laughed with derision.

Again. Sherlock noticed Harry's reaction to the word freak. It was barely notable the second time, compared to the first that had completely jerked him out of his almost panic attack. For whatever reason, the fact that Sherlock was called freak and no one had anything to say about it made Harry square his jaw and look at Sherlock with a sense of kinship.

"I want to live with Sherlock," came the small, soft, but certain tone from the bed. The adults went silent and stared at Harry, who was staring resolutely back at them.

Donavon bent over silently, "sweety-"

"My name's Harry."

She smiled tensely, "Harry, you don't want to live with him. He's dangerous. He gets people hurt."

John looked indignant on Sherlock's behalf but didn't correct her. Sherlock really wasn't the sort of person you entrusted children to. Harry didn't blink an eye, if anything he looked more determined. Sherlock scoffed.

"That's not going to perturb him in the slightest Donovan, the child has been on the front lines of an underground war for the last year. Danger is what he knows best," Sherlock turned to Harry, "you can't come and live with me. I don't have any room. There's only one spare room and John's using it. I don't have time in my schedule to look after a child, I have important scientific experiments all over the place which you would inevitably get in the way of or sabotage, and I work at odd hours of the night and day which would be ruined by the need to keep you on a normal schedule. No, I can't have you living with me and getting in the way."

Although now that Sherlock was thinking about it, that would be a fantastic way to observe Harry more closely when he was relaxed and less wary- no, that was a bad idea; he wasn't a day care centre. Not even for ex-child soldiers. Hmm that sounded like a good idea for a potential experiment.

Lestrade looked annoyed at Sherlock, but nodded anyway, "it's really not possible for you to live with Sherlock. We need to do this by the book as much as possible and that means after you've told us all you can about... Well after you've been released from the hospital you'll need to go to foster care where they can look after you properly if we can't find your family. Even if we wanted you to go with Sherlock, my superiors would never allow it."

John smiled kindly, but apologetically at Harry, "it is for the best I'm afraid. You need stability in your life if what Sherlock said was true and we could never give you that."

Harry just set his jaw mulishly, "I want to live with Sherlock and John," he insisted strongly.

Sherlock sneered, "even if I wanted you, which I don't, and I had the room, which I don't, and the police would let you, which they won't, my brother would never allow you to come and live with me."

Harry said nothing, but narrowed his eyes minutely at them all. It was a battle of stubbornness between Scotland Yard, John Watson, Sherlock Holmes, the British Government and Harry

Lestrade, unlike the other adults in the room, knew just how unreasonable kids could be when they set their minds to it. This one looked like he was getting ready to be particularly unreasonable. Instead of allowing it to escalate into who could be a bigger child, an eight year old or Sherlock Holmes (and it was saying something that he had genuinely no idea what the outcome would be) he decided to nip it in the bud.

"Right, well why don't we all take some time to cool down and come back to this conversation later. Sherlock, John, come outside with me. Donavon keep an eye on the- Keep an eye on Harry. There's no point in talking about him going anywhere until we've got his medical report."

Sherlock and Harry gave an identical terse nod, glaring at each other, before Sherlock swept from the room, his coat tails flapping.

* * *

Just as the four hour mark hit, back at 221b Baker Street, during which Sherlock had been brooding on the sofa with hands in the 'thinking position', no doubt still caught up in the puzzle that he had found in Harry, Sherlock's phone rang. He ignored it as it continued to ring.

"John," He commanded. John sighed -'bloody lazy sod'- and exited the kitchen to fetch his own (stolen) phone from Sherlock's pocket to answer it.

"It's Lestrade. The medical report's done. He thought you might want to take a quick peek at it. Apparently it's a bit unusual," was all John managed to utter, before Sherlock was off the sofa like a shot and running downstairs.

"Come on John! We have an eight year to interrogate some more!"

"Sherlock!"

On the way to the cab, Sherlock was steadily ignoring John who was ranting to him about sensitivity and trauma and bla bla. Predictable. Boring.

"Besides, you've already asked all the pertinent questions. The case is as closed as it's going to get now that the killers are dead, even if we don't know their identities or where their bodies are."

"Wrong. Sometimes it astounds me at how little you observe John. I can't fathom how you notice so little around you."

John scowled heavily, "fine," he bit out, "what are you going to ask."

Sherlock glanced at John, "I've upset you. Don't be. You're far more capable of intelligence than most other people. You just have it switched off the vast majority of the time. Now think John. What was unusual about him?"

John quirked his eyebrow, "he looked a lot like you, just with green eyes?"

Sherlock rolled his eyes, "dull. You're noticing the obvious things. Think more about the details. What did you see."

John shifted and sighed exasperatedly, "oh I don't know Sherlock. I'm no good at this. He's a child soldier. He's very mature and smart for an eight year old, or even for an adult actually. He's fairly emotionally closed off."

Sherlock waved his hand dismissively, "I'm not interested in his emotions right now I'm talking about his physical state."

"Er... He looks malnourished."

"Better."

"He's got a bunch of scars."

"Yes! And?"

"And I think a weird symbol drawn on his wrist."

"Exactly!"

"You want to ask him about a drawing?"

"Not a drawing. A tattoo. Two to be precise. One on his left forearm and other on the inside of his right wrist. They clearly mean something and I want to know what."

"I didn't see a tattoo on his forearm."

"That's because it's white and therefore barely visible. It looks more like a faint scar. That and of course I want to know about his and his friend's scars but those will have to be asked when there's more trust between us. People are notoriously touchy when talking about scars for some reason. Especially when they've been tortured."

"Tortured?!"

Sherlock looked at John with disdain, "of course John. What else would you call having words carved into your flesh. I suspect at least one of his other scars have been inflicted by torture too."

"You're not going to ask him about his time being tortured Sherlock!" John demanded angrily.

"Is that not what people do? Talk about their traumatic experiences to help them get over it?" Sherlock asked, only half faking his confusion.

"Yes, but with someone who is capable of empathy and emotional understanding. That is certainly not you. He can talk about it to a therapist to help him."

Sherlock sneered at the idea, "and you think some therapist will be able to empathise with him about being abused growing up, before being shipped off into a secret society filled with racists and bigots who expected him to save them all and tortured him when he tried, then forced him to become a child soldier who obviously killed people and was likely tortured with his friends once again, only to be locked in a cell for months on end, and finally escaping to kill a bit more so he could fake his own death and search for his missing friends who- oh, turned out to be dead all along. He's never going to properly confide in someone completely inept like your therapist John. I suspect we won't find anyone who can empathise with him as much as you and I."

"Sounds like you're advocating for Harry coming to live with us," murmured John with a teasing smile.

Sherlock pursed his lips and reluctantly admitted, "having given the situation some thought I have decided that were Harry to find himself capable of convincing everyone he should live with us, I might not find the situation as disastrous as I had initially thought. He is... competent in suppressing the utter idiocy that plagues most people."

John snorted, "right. You could have just said 'you wouldn't mind it'."

Sherlock merely smirked in reply.

They arrived at the hospital less than twenty minutes later, Sherlock's coat tails flaring out behind as he stormed along the corridors and approached Donavon, who was outside the room.

She sneered at Sherlock, "you can't enter freak."

"Ah, Donavon, it's nice to see you found another use for Anderson's table other than eating off it. I hope you wiped it down before his wife used it again," Sherlock replied with a fake smile, "now if you'll excuse me, someone needs to do everyone's job around here and since I'm the most qualified not to be an utter imbecile I think it had better be me."

John coughed into his fist in an attempt to hide his smile from Donavon. He generally liked to remain impartial when Sherlock and the police were involved since they were doing their best and he really was rude to them, most of them were saints for putting up with him. But Sherlock was right in that compared to him they were all idiots. However, since Sherlock had returned from his fake death John had discovered a new found appreciation and patience for Sherlock's vicious and witty insults aimed at nearly everyone he came across. Well that and he just generally didn't like Donovan.

"What, they're going to let you anywhere near that child again, after last time? You've got to be joking. We all know how well it goes each time you try to talk to a sensitive kid," She smiled nastily. There was a barely noticeable pause in which John could see Sherlock's jaw tighten as he recalled the child's scream that had initially cast suspicion his way and had eventually led to his painful separation from everything he knew in England for years.

"I was invited here by Lestrade. Where is he, since clearly he's the only person on the case who isn't completely brain dead."

Donavon sneered again, opening the door reluctantly before she called in, "the freak's here to talk to the kid."

John noticed Sherlock's back stiffen and his jaw clench angrily, perplexed. He usually hardly even noticed when Donavon called him a freak.

Lestrade gave Donavon a sharp look to reprimand her about her professionalism in front of a child no less. Donavon clenched her jaw and avoided eye contact with everyone sulkily.

John entered the room behind Sherlock, noticing the Doctor holding the boy's medical report and Harry looking uncomfortable with so many people in the room.

"We've tried to ask him a few questions concerning his medical report, but he just refuses to reply. Since you're a doctor and he seemed more at ease with you two we thought he might talk to you," Lestrade muttered to the two.

The doctor nodded and reluctantly handed the report over to John, whilst Sherlock was once again staring at Harry like he was a gripping puzzle. Harry, rather than acting perturbed at the examination was looking back at Sherlock with what could only be described as relief.

Sherlock realised with considerable surprise, that Harry had placed a tentative trust in him, most likely due to Sherlock's obvious status as someone who stood outside of the norm, someone who didn't fit into this society, like Harry, someone who was different. It was a novel experience for someone other than John to feel infinitely more comfortable with Sherlock because of his ability to see the secrets people generally didn't want made known, because he was considered a freak.

"Give us some time to talk," Sherlock replied, still not looking away from the boy. Lestrade glanced dubiously between John and Sherlock.

"I'm not sure that's such a good idea. You're not exactly known for being... Sensitive, and after last time..."

Sherlock scoffed, "the boy was abused, I wouldn't be surprised if he's heard every insult already from his relatives, on top of everything else. He's more than likely to be untouched by anything I can throw at him."

If anything Lestrade looked even less convinced. Sherlock rolled his eyes impatiently. He didn't need John to subtly scold him to know he needed to give some ridiculous false platitude to appease the D.I.

"Fine. I'll be... nice," he bit the word out as though it were distasteful. Lestrade gave him a doubtful look but turned to leave with the doctor who looked equally as doubtful.

"If I come back in and you've made him cry, I won't ask for your help for two weeks," he replied as he left the room.

There was a long pause before John realised Sherlock was peering at him purposefully.

"I'm not leaving you in a room alone with him."

Sherlock said nothing, but narrowed his eyes minutely at the doctor. It was a battle of stubbornness between the two that John inevitably lost. John clenched his hands, thinking furiously about idiot best friends who thought it was a good idea to interrogate an eight year old without anyone there to tell him when he went too far.

"Three minutes," he warned, before he left Sherlock and Harry alone. Sherlock barely noticed since he and the boy who looked like he could be Sherlock's son were staring at each other again.

Finally Sherlock spoke, in a softer tone than he usually used.

"You got called freak enough that you began to identify with that word as your name. Who called you freak?" It wasn't the most important question to ask, but despite popular opinion, Sherlock did know how to be considerate and he was well aware he wouldn't get anywhere without slowly making Harry warm up to him again.

The boy gazed at him steadily for a long while and the detective wondered if this was how exposed people felt whilst he deduced them.

Eventually he opened his mouth, "my aunt and uncle. And then the others too."

Sherlock pondered if 'the others' meant those who called Harry a liar, or those who saw Harry as the enemy. He dismissed the thought as irrelevant.

"Do you believe them?"

Harry shrugged, "I guess. I don't think it's a bad thing mostly. I just don't like the word."

Sherlock hummed, "it would be prudent to hide a weakness like that. Even a small one can be exploited." Harry nodded once solemnly.

"Will you take me to see their bodies when I'm out?" Harry asked tentatively, "I just want to see them one last time. To confirm that they're really gone."

He considered the request. It would certainly make Harry trust him more and bring him closer to the child so he would be less wary around him. Plus he would end up visit the morgue anyway some point soon so he might as well bring the boy along.

"As long as I won't end up having to be a shoulder to cry on, and provided you answer my questions about your medical report honestly."

Harry took a moment to think about it. Good, he wasn't just going to blindly accept someone's words at face value then.

"Deal."

At that moment John walked back in eyeing Harry carefully for any sign of upset, fear or anger. The usual emotions after exposure to the man.

"I've had a look at his medical report," John whispered in Sherlock's ear.

"And?" John pointed to four things that stood out as abnormal to John, and Sherlock's eyebrows raised in surprise.

"What?" Harry asked concerned.

John cleared his throat and turned to him, "well there are a few issues. You're malnourished, which can be fixed over time but it will probably stunt your growth a little in the end. You're low in iron and you're still dehydrated. Also you'll need to eat the right foods and take some supplements to help your bones. These are all as a result of your difficult up bringing..."

Sherlock huffed at the wording and muttered some choice words under his breath.

"He wants to know how you got around 100 grams of sand lying at the bottom of your stomach," Sherlock stated, much to John's annoyance.

Harry's eyes bugged, "100 grams? Are you sure?"

"That's what it says in the report," John replied. Harry scratched his head in confusion, giving John a look at the barely noticeable tattoo on his forearm, but he couldn't make out the shape.

"Huh. I don't remember swallowing that much," Harry murmured absently.

"Why on earth did you swallow that much sand?" John raised an eyebrow at the boy.

"It was contained. Initially. And it was hidden in my mouth. It was important for my escape attempt alright," he added defensively at seeing the men's twin expressions, "but the container sort of ripped when I was knocked down, and in the struggle I swallowed the sand."

John looked sceptical and opened his mouth to question further before Sherlock interrupted, "a perfectly reasonable explanation. But what really matters is how long the sand has been there since it isn't showing any sign of passing through naturally."

Harry thought for a moment, "about... ten days before I managed to actually escape I think."

A funny expression crossed his face for a moment before it was gone again. John was too worried to notice.

"That's probably going to have to be removed by the hospital then as soon as possible." He made a mental note to talk to the doctor when he handed the report back.

"You also seem to have a small chip of something stuck in the bone of your right arm, which correlates with a scar I've noticed there. A round, curved and tapered object entered through your arm and just out the other side."

Harry shifted in his bed and avoided eye contact, "is that so?"

Sherlock's eyes narrowed, "yes. It is. And it needs to be removed."

Harry's eyes widened in panic, "No! No, I'm fine. It's not necessary really."

"It's fantastic that you've rediscovered your medical degree and have the experience to override myself and the hospital in this matter. Really it is. I will of course take your learned and professional view of the situation into account. In the mean time, you're having that object removed from your arm," Sherlock smiled sarcastically. Harry gritted his teeth and took a deep breath.

"I refuse," he ground out.

"That's wonderful. Do you hear that John? He thinks, as a minor, he has a say in it. How sweet."

"Sherlock," John warned quietly, mindful of Harry's increasing temper. He had a feeling if it exploded they wouldn't just be dealing with a childish tantrum.

Sherlock ignored John, too irritated at what he perceived to be Harry's naive stupidity showing through to observe the risk.

"Luckily we don't need your cooperation. It's easy enough for us to drag you kicking and screaming into the operation room, render you unconscious against your will and remove the chip all with your refusal."

Sherlock looked back at Harry and faltered. His eyes had darkened, the anger removed entirely from his face. He looked cold, grim, determined. Sherlock imagined that was what the people he killed saw. It was frankly disturbing to see on his young face. When he spoke his voice was cool and detached.

"I categorically refuse to submit myself to the operation. That chip of bone has been there for some time now and it will continue to be there for years to come, if not the rest of my life. That fact I absolutely promise. If you attempt to have me subdued and forced into the procedure I will be out of this hospital immediately and none of you will ever find me again. Whoever gets hurt in the attempt to restrain me will not be on my conscience."

Sherlock found himself, for once, speechless. Both he and John nodded silently. John didn't think he'd ever been intimidated by someone so young and frail before. Often when Harry talked he came across as solemn but innocent. Smart but with an edge of naivety to him. Emotionally mature but still carrying the optimism of youth. It was easy to forget he had also killed an unknown number of people and would probably have few qualms about doing so again if he perceived it to be necessary.

And that was what was frightening. Neither Sherlock nor John knew yet how easily Harry might perceive it as necessary.

Sherlock on the other hand, was digesting the information that Harry had inadvertently shared; he had been stabbed with a piece of bone. A fang or claw going by the shape it would have had to be from entry and exit scars. But he couldn't think of a single animal that had a fang or claw that size and shape. Unless it had been artificially altered from a larger bone. But what was the point? It was an inefficient shape for a hand held weapon. This would need further study at a later date.

"There is of course the oddity that is the rest of the bones in that arm," Sherlock added after a suitable pause during which both men rapidly got over and ignored that they had been successfully threatened by a child.

"The rest of the bones?" Harry asked, genuinely confused this time.

John decided to take over before Sherlock pushed the kid to add in some death threats next, "whilst the bones in the rest of your body have suffered from your diet growing up, the ones in your right arm are absolutely fine. It's as thought a you who live under perfect conditions gave them to you. It stops at the shoulder. Is there a condition... Or any reason you can think of that explains that? It's just a bit, well, strange."

Harry was utterly perplexed for about five seconds as he thought, before realisation hit him. He couldn't very well tell them that he had had all of the bones in that arm completely regrown by the help of a potion when he was 12 could he? They'd think he was either mad or a liar. He carefully kept his expression on perplexed before he finally shrugged, appearing baffled.

"I've never had an X-ray before so I didn't know they were any different," he thought he'd successfully gotten away with it, and technically wasn't a lie, until he saw Sherlock's look of suspicion. But the man didn't call him out and so John moved on, satisfied with the answer.

"Don't worry. I'm sure it's nothing dangerous, but if you ever become concerned over pain, stiffness or anything else unusual in that arm make sure you tell someone."

Sherlock huffed impatiently, "while this has been enlightening, what's really important is the unknown compound in you blood."

Harry's features tightened minutely, "what do you mean?"

John checked the report carefully, "we're not too sure, but at first glance it looks to be an extremely deadly and undiscovered poison, which is bound to what appears to be a neutralising agent."

Harry frowned, "what?"

John tried to reword it, "you have a mystery deadly poison and its antidote floating around in your bloodstream. Instead of having been removed from your body over time it seems to just... be there. I'm not sure if it's had any adverse or even positive effects on you since I don't know what either of them are. Could you give us a clue?"

Harry shifted in his bed again, "oh that. I got bit by a snake a few years ago. I'd never seen it's type before or since. At the time, I was given the antidote by someone who knew what they were doing and the situation was a little intense so I didn't ask what it was. It worked, obviously."

"Could you direct me toward the person who gave you antidote if at all possible?" John sighed, not expecting him to be able to.

Harry smile apologetically, "He didn't speak English. And also he left just over a year ago and no one knows where he went and no one's seen him since, sorry." Again, technically Harry hadn't lied. He just hadn't told the whole truth either.

"I want a sample of your blood to study it further," Sherlock demanded imperiously.

"Sure," Harry agreed with a shrug before John could reprimand his flat mate, "on the condition I get to come and stay with you instead of going to foster care."

Sherlock's lips tightened in annoyance. He didn't want something that could prove an excellent distraction hanging off of something as unsure as the boy's living arrangements. He'd have to pull in a few favours that he'd been planning to save for a rainy day.

"The topic is still in discussion. But I will do my best to arrange for it. Even if I have to ask Mycroft," he added the last bit with a deep grimace that seemed almost pained.

John whistled in surprised, "you know he means business when he offers to go to his big brother for help."

"Shut up," Sherlock growled, he glared at Harry, "if you come and live with me you had better not complain when I play the violin or don't pay attention to you all the time, or perform my experiments."

Harry just smiled innocently in reply.

"You'll be out of here in a few days. In the mean time make sure you eat and drink well," John suggested kindly, and Harry nodded in response.

Sherlock walked to the door with a grumpy expression, before he spun round to the bed, "what's the significance of your tattoos? What do they mean."

Harry raised his eyebrows in surprise for a moment, before he grinned impishly, "if you can find out successfully what they mean before I leave here I'll answer any ten questions you have for me honestly to fullest capacity I can."

Sherlock narrowed his eyes in a mixture of grudging respect, excitement at the challenge, and annoyance at being denied, "fine," he snapped, wrenching the door open and storming out.

John just chuckled and shook is head in wonderment. The boy had probably just cured Sherlock of his boredom for the next three days with just a few sentences. He couldn't wait to see what he could do with some planning, time and more knowledge of Sherlock's character.

"See you soon Harry."

"Bye John," he called out chirpily, clearly a bit smug at his achievement.

"This is either going to be highly amusing or a complete nightmare," John muttered to himself as he left.

"John! I need your laptop!"

* * *

 _What do you think? I hope I portrayed Sherlock well enough. He did have answers to how he found out about all the things he deduced from Harry which weren't explained but the chapter got way too long going through it all._

 _Also one thing that occasionally bugs me a little is the fact that in all the stories of Harry Potter and orphanages being mentioned, no sign is given to acknowledge the fact that there are no longer any orphanages in England. There are places kids stay in between foster homes which are like orphanages, but generally the system tries to get orphans to foster parents._

 _So I gave lots of little clues and few solid answers. Would would you guess happened to Harry to put him in that situation?_


	2. Chapter 2

Disclaimer: I own nothing but the general plot and OCs

I'm seriously amazed and thankful at the crazily supportive and interested response I got in response to chapter one of Mystery Child. So much gratitude here! I loved everyone's guesses and curiosity at what had happened to Harry.

Compared to last chapter I feel like this one is lacklustre and is also shorter, but no matter how much I poked at it this chapter refused to go anywhere after a while so I ended it here and decided to try again next chapter.

Also in terms of season 3/4 canon, I'm not getting rid of it in its entirety but I'm definitely tweaking significant aspects of it. This fic isn't just gonna be Sherlock and Harry and John plus some of the other characters popping in, with cases getting a summarised mention. Once Harry has settled in, the formula of the tv series will be reasonably similar to the way I approach the writing.

Having said that, the way the writers write Sherlock is by taking inspiration from _some_ ACD stories massively and constantly sprinkling references to _other_ ACD stories throughout, combined with a fair bit of modern originality. I obviously won't be doing anywhere near as masterful a job but that's basically my plan, with some original cases, some ACD inspiration, some changes Harry's presence would cause and some purely magical focussed bits.

Thank you so much for awesome reviews, as well as favs and follows! Let me know what works, or what doesn't work for you, as well as any prompts for scenes you'd like to see.

* * *

 **Chapter 2**

Sherlock was sat sulkily cross legged on the sofa. He had been in that exact position for five and a half hours, after creating the most god awful sounds on his violin for two. John sighed as he put the kettle on.

"Come on, Sherlock. I thought you were amenable to the idea of Harry coming to live here. We'll just have to be careful about which experiments you leave lying around. We'll need to buy him some clothes, and make sure he gets regular meals. Find... something... For him to do all day even if it's spending time with Mrs. Hudson. It won't be too bad."

Sherlock just snarled wordlessly for a moment in order to emphasise his next assertion, "I'm not making any concessions for that insufferable child. My experiments are staying right where they are. I'm not shopping, or cooking or cleaning. I am not altering my timetable to suit the whim of an obstinate brat. The Work is all that matters to me and he is not getting in the way."

With that he dramatically lay down and faced the back of the sofa with a flip of his coat tails. John chuckled at the physical melodrama.

"I know that's not what your real problem is, Sherlock. But really what did you expect? Of course Mycroft was going to want to meet the child that was important enough for you actually go to him about and deign to ask a personal favour. Surely it's a good thing that they get along and Mycroft has agreed to this, even if it's just on an interim period."

Sherlock merely made a disgruntled noise and ignored John, who rolled his eyes.

"I thought you said Harry was tolerable. It's not like he's going to be a spoilt tantrum thrower- unlike someone else who lives here," he added under his breath.

"Besides, I have it on good faith that Harry likes Mycroft less than Mycroft likes Harry."

Sherlock hummed thoughtfully.

"I believe the exact words were, 'a controlling man who feels the need to know absolutely everything about everyone, even things which are none of his business, and is determined to prove he is the smartest person in the room, when he really just needs to stop congratulating himself'. All that from one ten minute meeting," John only half made up - well that was the gist of the kid's comment. Thereabouts anyway- John figured he couldn't exactly be expected to rattle accurate quotes from non-famous people off the top of his head like Sherlock could.

There was a pause before Sherlock reluctantly admitted, "he is less brain dead than most children his age."

"There that's practically an admission of his genius," John replied with a grin.

"He's hardly a genius, John. His skill set doesn't lie in his ability to do advanced calculus or particle physics. He was a soldier. He knows how to deal with people and danger."

"Well he's going to need all his skills in dealing with people to put up with you when you're bored, so I'd say that's a good thing," John teased, as he switched some crap TV on.

"Are you going to watch Jeremy Kyle?" Sherlock asked curiously, peering over his shoulder at the TV.

"We agreed not to after last time."

"Humph," Sherlock went back to looking at the back of the sofa grumpily, as as John calmly sipped his tea.

* * *

Molly was sipping her cup of coffee and observing Sherlock out of the corner of her eye in what she thought was an inconspicuous manner. John shook his head despairingly at the two; even after two years of being away she was still caught up in mooning over a man who was 'too busy for sex, let alone a relationship' according to himself, and Sherlock was still a right bastard who had no problem with manipulating Molly's affections to his own advantage before callously dismissing her. It was like he'd never left sometimes.

John could see that Sherlock was close to a temper tantrum. It had been building up all day as the time ticked onward for them to pick Harry up from the hospital and Sherlock came no closer to discovering the significance of the two tattoos on the young boy. Finally Sherlock slammed the lid of John's laptop down and pushed it aside with a snarl.

Molly jumped in surprise, sloshing coffee down her brand new shirt and John quirked an eyebrow.

"This doesn't make any sense, John!" Sherlock snapped, glaring at John as though it were all his fault.

"No luck then?" John was a just a tad amused at Sherlock's aggravation with not knowing something or even how to get his hands on the information.

"There's no obvious reference to either tattoo anywhere on the Internet, and according to police databases, it's not connected to any gangs. It's not from any culture that I could find, nor any religion."

"Well maybe that's the point. He doesn't belong to a culture that you could find on the Internet or any obvious books. You're probably looking in the wrong places," John sensibly pointed out. Sherlock just pouted at the idea of losing for once.

"Why don't you have a look at his file?"

Sherlock's head snapped up, "what file?" The doctor sighed in exasperation.

"The file Mycroft gave us after he did a background check on the kid. After he agreed to sort out the paperwork to let him stay with us as a favour. Remember?" John rifled through the files on the countertop as he talked before he came across the correct one and handed it to an impatient Sherlock.

The detective snatched it out of John's hand and opened it up eagerly, only a little sore at having to rely on information his brother had procured for him.

"Parents died in a house fire," Sherlock scoffed, "hardly as accidental as the file states."

Grandparents died before he was born in a house robbery gone wrong- unlikely to be true- cancer and suicide shortly after. Bla bla bla, boring. Average to low grades, low attendance, clearly a result of the abuse. No previous doctor or hospital visits, no previous inoculations. Went missing a few months ago, reported by the school. Upon police questioning, relatives were arrested on suspicion of murder after traces of the boys blood was found underneath the stairs along with a bed. Trial ongoing.

"There's nothing in this file of any relevance," Sherlock huffed, and threw it back to John. John merely shrugged.

"His birthday's next week. He'll be nine," John offered.

"Oh brilliant, genius John, you've cracked the case of his mysterious tattoos. It's all about his birthday," Sherlock retorted scathingly.

"There's a nine year old with tattoos?" Molly gasped in surprise.

"An eight year old with tattoos, Molly. His birthday is next week, do keep up," he rolled his eyes.

Although he'd claimed to file was of no relevance, it did share one important detail; Mycroft was as in the dark about Harry as Sherlock was. The file described a plain, boring, predictable mistreated orphan who went missing. Not a child soldier. No doubt Mycroft had gleaned as much as Sherlock had from his ten minute meeting with Harry, and decided to place the boy somewhere he could keep a close eye on him.

Sherlock's offer was probably the perfect opportunity; an excuse for increased surveillance on his little brother and on Harry in one go.

Sherlock's phone dinged as a text came through.

 **You need to pick up Harry ten minutes ago -GL**

 **Mycroft's here as well -GL**

Sherlock growled under his breath about insufferably nosy siblings, threw his coat and scarf on and dramatically exited the building with John trailing behind.

* * *

By the time Sherlock entered the hospital Lestrade had texted a further eight times and called twice. Apparently he found Mycroft creepy. John couldn't disagree.

Mycroft was waiting out front for them, smiling with polite patronisation.

"Brother, late to pick up a child in your care isn't the best start."

Sherlock brushed past him rudely, "you were here. It's not like anything would happen to him."

Mycroft sighed, "Sherlock, at least try to act responsible. You'll be in charge of another person's life constantly now. You can't just delete him when he becomes inconvenient or boring."

"I've had a pet before Mycroft, I know what's required of me."

"Sherlock!" John hissed. Sherlock had the decency to look contrite for a moment. Just a moment though.

"Fine. If it's what you both want to hear to make yourselves feel better; I promise to make sure he's fed and watered and that he sleeps well after he's tucked in with a bed time story and a glass of milk once he's been given a good night kiss," he mocked. Mycroft heaved a long suffering sigh.

"I've bought him a new wardrobe, and I've made some minor alterations to the flat to make it more child friendly. I'll enrol him into a decent school and arrange transport too, starting in two weeks. If he lasts that long. He'll need to be tested to see where he is along his education."

Sherlock looked furious at the information that Mycroft had changed his flat in anyway.

"Thank you for your sincere care Mycroft, but _I_ can find a school for him without your assistance in the matter. Good day brother," he spit venomously over his shoulder.

"Sherlock, just remember. We know very little about him and he seems adept at lying. I wouldn't get attached to his presence if I were you."

Sherlock sneered and ignored him resolutely. Mycroft arched a brow at John who was suppressing a grimace. Sometimes he really couldn't stand the things Mycroft said to Sherlock.

"Good day, John," Mycroft nodded to him and then left, umbrella swinging by his side.

There was a heavy silence as John and Sherlock walked side by side, Sherlock avoiding eye contact with John in the hopes of putting off a dull conversation about his _feelings_ or some other equally boring sentimental drivel. He sighed internally when the doctor cleared his throat pointedly.

"About what Mycroft said..."

Sherlock stopped abruptly and turned to face John.

"Mycroft has imparted with a lot of words in my presence, very little of which I listen to and even less of which I haven't deleted. You'll have to be more specific, John," Sherlock replied, being purposely belligerent. John gave Sherlock a knowing look.

"About not getting attached to Harry being around," he hesitated, trying to find the right words. Sherlock butted in before he had the chance.

"A sound piece of advice. Of course, he needn't have wasted my time telling me what I already knew, but then my brother does so enjoy doing that." John hated it when Sherlock wore that impassive mask of his. It was always when he was determined not to act like a human being with emotions. Just a cold logical machine. It was when he was resigned to disappointing John with what he was about to say.

"Look, there's nothing wrong with getting close to people, Sherlock. You said so yourself that the kid isn't as oblivious as most people, I don't see what good can come out of this if you insist on keeping him at arms length when he comes with us. You can't just go through life acting like you don't care about anyone," John ranted, becoming more frustrated with the detective as he spoke.

Sherlock, ever the stubborn man, refused to make eye contact and his expression didn't even flicker.

"Of course I can, John. It's far easier than one would expect. I have said so before, but perhaps you need a reminder; sentiment is a weakness. It is a dangerous flaw that is easily exploited by enemies and I am not going to allow a physically weak child with average wits to be my Achilles heel. Getting attached to that child would not only be illogical but stupid.

"He's coming to stay with us because for now he's my one and only source of information on an entire society that I had no idea existed, and he will leave when I have learnt all I can from him. He isn't coming to stay with us so we can be raise him and play happy families. Love is a distracting factor which might throw a doubt upon all my mental results.

"He is and will remain a means to an end and as such, yes John, I will be keeping him at arms length. I suggest you do so as well lest you fall prey to dangerous emotions like _love_ ," Sherlock spoke the last word with heavy contempt, but besides that his voice and face remained cold and emotionless.

Sherlock watched silently as John struggled with his disappointment, anger, and various other cocktail of feelings that confused the doctor.

"And what about me? Do you keep me around because I'm a means to an end, making sure you never care at all because I'm just your stupid flat mate and God forbid you actually give a damn and someone hurts you for it. Because that's a very sad way to live Sherlock. Or do you care about me because I'm not physically weak so that's ok? And what about if I was hurt and became disabled, or infirm. Would you cut me off? Delete me from your mental hard drive because I'm no longer convenient?" John's eyes were hard, and there was a clear current of anger underneath his quiet tone.

There was momentary pause, in which John decided he didn't want to know the reply to that and continued walking. As such he didn't hear Sherlock's murmured answer.

"I cannot afford another Achilles heel like you."

* * *

John stood behind Harry on the landing just outside their flat, with the door mostly closed and various crashes and bangs reaching them from inside.

"No, no, _no_! It's all wrong in here! That doesn't go there, and- oh, for- _NO_! He's ruined it. It's all ruined. All my experiments!" Came Sherlock's litany of aggravation from inside, as the bangs increased.

Harry turned his head to glance with mild concern at John, and bemusedly asked, "is he okay?"

The shadenfreude John felt on the inside was mostly hidden from his features, but not entirely. He shrugged in reply, "he's just throwing a tantrum because his older brother cleaned his room before he was done playing. He'll be fine once he's had a sulk."

"Right," their new...kid? replied, his tone dubious.

Just in time for the cessation of noise inside, John's phone began to ring. Looking down he saw Mycroft's name, and with a sigh, reluctantly answered.

"John, how are you finding the rearranged flat?" The older man's smarmy voice enquired.

"Yeah, well Harry and I haven't actually walked inside to see it yet, but somehow I don't doubt you already know that."

"Hmm, quite. Let me know if anything is missing from your new ward's possessions, I did specify age appropriate toys and reading material but then the Holmes' standard is often so very... cerebral shall we say, compared to the general masses. It can be difficult to accurately predict just how much a person won't understand."

"Why do I get the feeling I'm the one being called an idiot and not the kid? Whatever it doesn't matter, what do you really want, Mycroft?" John huffed a little, his patience running thin.

"Very well, lets skip the pleasantries. I've ensured that Harry has a week to settle in and become accustomed to Sherlock before any officials come knocking for my little brother's expertise. Perhaps by that point he'll have come to some sort of resolution about the mystery child, and we can move on from this silliness."

"You don't think he'll be interested in Harry for long enough to start school do you?" He accused, feeling irritation build at the casual dismissive callousness that both Holmes' were prone to.

"I think that Sherlock will not find the addition of a child in his life to be fulfilling in the way so many claim. My dear little brother adores the spotlight, John. I can't imagine he'd appreciate having to share that with anyone, and children need attention. I think Harry won't last long."

"Well I think you're wrong. I think Sherlock is a lot more capable than you give him credit for."

"Perhaps. I give it two months at the latest, and I'd love to be proven wrong this time. Goodbye, John."

"Prick," John muttered, despite there being no one on the end of line.

"Can we go inside now?"

John jumped, as the young voice reminded him of Harry's presence. He was momentarily flustered at what Harry had almost definitely overhead, but he soldiered past the awkwardness and cleared his throat.

"Ah, um- oh, inside! Yes, yes, lets get you settled in."

Walking inside to the living room, they were met with the sight of Sherlock bent over with his head stuck in the fireplace surrounded by books and papers strewn on the floor as a result of his fit.

"Sherlock? What are you doing in the fireplace?"

"Mycroft has had plenty of time to get his fat paws all over the place while he wrecked our flat with his _redecorating_ ," he spat like it was a dirty word, "I'm sweeping the place for recorders of any kind."

"Ah," John acknowledged, taking a proper look at the place. The flat was probably tidier than he had ever seen it, even with the mess on the floor.

The carpet had been replaced and no longer had the chemical stain in the right corner that had infuriated John at the time it had happened, but after a while had just become a feature of the flat. There was a third chair by the fire, all the shelves were stacked neatly, and John noticed a small shelf close to the bottom which held non fiction and fiction books Harry might enjoy. The sofa was fabric now rather than leather, as well as slightly bigger, and all the smaller cupboards and shelves that were used for storage - mostly by Sherlock -had been replaced for something far more ergonomic and efficient.

The new coffee table in front of the sofa had a section underneath it which contained various board games and a couple of books. On the table that was placed closer to the window- also new and larger than the one before- lay a new phone and an iPad mini, with a small note that said 'For Harry' in Mycroft's ridiculously elegant handwriting.

"An iPad? That's a bit excessive isn't it?" John questioned Sherlock, who was now pulling the chairs apart and inspecting all the cushions.

"My brother might scoff at the idea, but he's petty enough that it would delight him if Harry favoured him over myself."

John almost made a dry comment about Sherlock claiming that Mycroft was petty as though they weren't just as bad as each other, but a quiet voice interjected before he could.

"What's an iPad?"

John jolted as he remembered Harry's presence, already caught up in the usual tempo of just being the two of them in 221b that he had forgotten the boy was there entirely. He made to reply, since Sherlock had already demanded on the way to picking Harry up from the hospital that the doctor was in charge of the 'stupid questions', but to his surprise Sherlock was the one to reply first.

"Here," he stood up and walked over to the table, throwing the phone to Harry who caught it with impressive ease in one hand, "I'm sure mine and John's numbers are already saved. Send me a text."

Harry looked blankly at Sherlock, and then down at the mobile in his hand. He hesitantly pressed the home button and blinked as the screen lit up his wary and baffled features.

He flipped the phone around in his hand and studied the edges, experimentally pressing the volume buttons, the sleep/wake button and the silent mode switch. It became immediately obvious even to John that Harry had no idea how to work an iPhone.

"There are only four buttons. Where are the rest of them?" The green eyed child asked, frustration creasing his brow.

With his hand held out in silent demand for the phone to be thrown back to him, Sherlock watched Harry with keen curiosity, his blue grey eyes practically glittering as his thoughts flashed.

With the phone back in hand the detective easily unlocked it and, giving the young boy full view of the screen, he texted himself and John a joint message so that they could save the number onto their own phones. The awe and confusion on the boy's face was evident.

"So what? he doesn't know how to work an iPhone. Not everyone grows up privileged, Sherlock," John commented, removing his outside wear in the futile hope that it would encourage Sherlock to do the same rather than walking on a brand new carpet in unclean shoes.

"You're comparing your own childhood exposure to technology, erroneously, to children growing up today. Harry here may have been neglected at best growing up, but he was in a wealthy enough household alongside two parents who spoiled their son rotten with material objects.

"They wouldn't have denied him a phone, and they'd have given him the best that they could buy. I don't doubt Harry has never held a mobile phone in his life by the way he handled this one, but to have never seen someone else even turn one on? Not in TV shows, movies, adverts, online videos, or real life?

"After all, his attendance may have been unreliable, but he did go to school with other children his age and I'm certain childhood hasn't changed that much that little boys and girls have suddenly become disinclined to boast to their peers," Sherlock rattled off his observations with speed, staring intently at an increasingly uncomfortable looking Harry all the while.

"Just because he's seen them before doesn't mean he'd know how to work one, he's not like you who could probably tell how to work one within moments of seeing it in someone else's hand."

"No of course not, but it begs the question of why it didn't even occur to Harry to touch the screen."

Which.. well that did occur to John as a bit odd but then he didn't know what kids did and didn't pick up these days without being directly taught, and he figured there was a reasonable explanation to it all, even if -knowing what he did so far of Harry's childhood -it was an unpleasant one.

"What do you suggest it means?"

Sherlock waved a dismissive hand in both John and Harry's direction, "I don't have enough data yet. It's a capital mistake to theorise before I have proper data."

John cleared his throat and glanced awkwardly down at the silent child, "right, that's fine and all but you have weeks to gather data and Harry's just standing around with nothing to do," he turned fully to the solemn faced boy, "Why don't you take your shoes, coat and scarf off and place them over- oh look we have a shoe rack now- over there. Afterward I'll show you around and see if we can find where Mycroft's placed the rest of your new things."

"I'll have some tea while you're at it," Sherlock absently demanded from where he was once more inspecting the flat for bugs.

John rolled his eyes, "tea, Harry?"

"Uh, sure. Please."

Once they were both stripped of shoes and coats John gestured for the child to follow him, "I'll show you the kitchen and bathroom while I'm making his majesty a cuppa."

He led the boy into the kitchen only to be faced with a glaringly obvious change.

"Sherlock!" He called, "What am I looking at?"

"It's a mini fridge freezer, John," Sherlock's muffled voice responded.

"Yes I deduced that for myself, thanks, but what's it here for?"

"It's for my experiments, and it has a magnetic lock on it so that childish hands can't ruin anything."

"Why do I feel like I'm the one being insulted," John muttered. It was a good idea though, and hopefully it meant no more instances of John opening the fridge only to find body parts contaminating the food.

He turned back to Harry, who was systematically opening cupboards and drawers and peeking inside them, one by one.

"Like Sherlock just said, Harry, the little fridge freezer is for Sherlock's experiments so there shouldn't be any in the bigger one. Help yourself to anything you find in there as long as it's in date. But if you _do_ find anything that...shouldn't be in there it's best not to eat anything and tell me," he gave a brief smile at the boy, who nodded in reply.

"Who does the cooking?"

Ah, John thought to himself, home cooked meals are supposed to be a thing now. Takeaway almost every mealtime wasn't really an option anymore.

"Mrs... Hudson?" He guessed uncertainly to himself, already feeling a little guilty for the unconscious assumption he realised he'd made that Mrs Hudson would be happy to take the bulk of Harry's meals on.

"You'll be able to get three days worth of meals a week from her, and a fourth dinner if Harry personally claims to be hungry on the day," Sherlock called, "of course I predict around a sixty percent decrease of tea and biscuits and an eighty percent decrease of cleaning from her as a result."

That succinct summarisation of just how much they could take advantage of Mrs Hudson's generosity really didn't do anything to assuage John's guilt.

"I can cook," Harry offered. John remembered the scars Sherlock claimed were from being forced to cook at too young an age on Harry's arms and made a face.

"Perfect. Problem solved," his socially oblivious flatmate responded, sweeping past them in the kitchen and opening each drawer until he found a rolling pin.

"No, not perfect. We can't make him cook like his relatives did," John protested, raising his voice to be heard over Sherlock gleefully smashing little bits of technology that were clearly Mycroft's bugs with the rolling pin.

"Don't be an idiot, John, we're not making him do anything, he offered."

"I don't mind," the boy assured, "as long as I can cook what I want to. I know quite a few recipes."

"There, see? And if I know Mycroft..." Sherlock walked over to their original fridge freezer and pulled it open revealing it full of ingredients that hadn't been there that morning. Sherlock scanned the contents and grimaced in irritation, "he knows I don't like beetroot."

After a hesitant pause the doctor heaved a reluctant sigh, "fine, but Sherlock and I are perfectly capable of doing the occasional cooking so don't feel like you have to."

"Yes, yes. We won't force you to cook and clean, we won't hit you or keep you under the stairs," Sherlock rolled his eyes.

"How do you know about that," Harry coolly demanded, his eyes narrowing and his body tensing defensively.

"You show minor signs of long term lead poisoning."

"What!?" John burst out in alarm, scanning the young boy but unable to spot whatever it was Sherlock had seen to lead to that conclusion.

"It didn't show up in your blood work because you've been missing from your previous residence for months and possibly due to that 'mystery' compound in your blood caused by the 'mystery snake' and the 'mystery' cure," the detective continued onward, putting sceptical emphasis on 'mystery' and ignoring John.

"What's lead poisoning and what does it have to do with anything?" Harry questioned, his green eyes still narrowed.

"It's a toxic metal that was used in the pipes and paint for houses before it was banned in 1992. That doesn't mean old houses aren't still equipped with it. You've lived in the same house almost your whole life, correct?"

"Yes," Harry replied uncertainly. John, on the other hand, cared less in that moment about whatever deduction Sherlock had made and more about the fact that he hadn't informed the doctor who would be the most responsible for the child's health.

"As I suspected. You were raised in a house that used lead, but you're only showing minor effects- in the pallor of your skin, where it's worsened your eyesight and your lack of growth, but most tellingly in the lining of your gums. Your relatives wouldn't have given you filtered water if they even had it, so theoretically you should be experiencing the same or worse symptoms than them. I've seen their pictures however and that theory doesn't hold up to the evidence.

"The other explanation is that the house had rooms painted with lead paint that you spent next to no time in. But as I've already stated, they were wealthy enough and they would have made sure each room was decorated to their standard even if they wouldn't spend any money on making whatever room you stayed in comfortable.

"This suggests you either had an attic or basement for a room. But then I noticed your X-Ray showed barely visible scarring on your lungs from sawdust you've inhaled consistently over a long period of time. The only wooden place in a house disturbed constantly enough to produce a consistent dust is the stairs. If you could fit under the stairs for an extended period of time, leaving the larger storage spaces free for their original purpose, why wouldn't people who prioritised keeping your existence as minimal to them as possible when you weren't making yourself useful keep you under the stairs? Thus, lead poisoning from the pipes, but less than your relatives who had much more exposure to the paint."

Harry stared at Sherlock with wide eyes, looking simultaneously impressed and chagrined, "yeah that sounds about right. So I've been... poisoned?"

"Not severely. The lead is no longer in your blood, or you would have been treated for it at the hospital. Over time your appetite should improve, you'll come to feel more energised, less irritable and you'll put more weight on."

"Harry why don't you check out the bathroom, it's through that door and just to the left," John levelly suggested as he glared at his flatmate.

The perceptive boy glanced between them before he gave a quick nod and left the kitchen.

"Why didn't you tell me he's had lead poisoning?!" He hissed furiously, trying to keep his voice down so Harry wouldn't hear.

Sherlock gave him a bewildered look, "I did."

"When?" He snapped disbelievingly.

"Just now. I know you're mentally slow compared to me, but this is a little extreme don't you think?"

The doctor breathed in angrily, ready to let rip on his best friend's blasé response to the health of a child that they were responsible for, when his brain translated what his socially incompetent flatmate meant.

"You only figured it out just now, you mean?" He clarified, and received his answer in the childishly petulant look Sherlock wore in response.

"Very few people on the planet could have come to that conclusion quicker than me," Sherlock responded in defence, mistaking John's question for an attack on his intelligence.

"Sherlock, I'm not... it's fine, I thought you were- never mind. Let's just get the tour over with. I'm tired and I have work at the clinic in the morning," John rubbed a weary hand over his face, suddenly feeling the long day like a physical weight now that he had admitted to his exhaustion.

Proving that their conversation had been less than private, Harry quietly reappeared the moment John spoke those words, and a part of John realised that living with a child soldier was probably going to mean a fair bit of paranoia from the kid.

"Which toothbrush is mine?"

"The one that isn't blue or white. That door past the bathroom leads to Sherlock's room. He prefers no one enters barring an emergency, but don't expect the same consideration from him in return, he's a bloody hypocrite-"

"Your room is shared with John," Sherlock butt in.

"Wait, what?" John felt quite indignant that he didn't get a say, although after a second of thought he realised it was also the only obvious option. There was no way Mycroft would have expected Sherlock to share a room gracefully and John had the bigger room.

"You'll probably find a futon or sofa bed in your room, as well as furniture containing his clothes, judging by the sofa in the living room."

"What about the living room sofa?"

Sherlock scoffed, "how you didn't notice that it's sofa bed is beyond me. During nights that I intend to sleep through until morning Harry can use it. He'll have your room to himself half the time anyway due to the on and off again girlfriend you think you've been keeping a secret."

"Right. I'm too tired to deal with this," John commented dully. Judging by the fact that Sherlock still hadn't taken off his coat or shoes the Doctor doubted that his flatmate would be sleeping any time soon, "come on then Harry, let me show you upstairs where my room is."

Everyone had eaten before Harry was picked up at the hospital, so he didn't feel obliged to do anything else that day besides get into his pyjamas, sleep for at least eight hours and try again in the morning.

Hopefully a full day alone with Sherlock would open Harry up enough that he'd feel more comfortable talking, considering the boy's obvious withdrawn attitude from the moment they'd gotten in the taxi. He was clearly capable of standing up for himself and if nothing else spending an extended time with Sherlock was bound to aggravate anyone enough that they crumpled like wet paper or were pushed into asserting themselves.

He felt like there was something he was forgetting to tell the detective, but he brushed the thought aside and led Harry onto the landing so they could go to his room and find some night wear for the boy.

"John, you forgot to make me tea," his arsehole of a flatmate called after him.

"Oh, piss off and make it yourself," he grumbled, certain that he could hear quiet laughter behind him from both the detective and his mini lookalike.

* * *

 _How do you think Sherlock and Harry will fare alone together? What do you think going to school will be like for Harry?_

 _In terms of the timeline of both Harry Potter and Sherlock combined that's part of the mystery._

 _Just know Sherlock returns sometime between October and November 2013 and season 3 kicks off early Nov 2013. I've pushed the timeline around so that Sherlock returned on the same date, but it's now the beginning of Jan 2014- time for John to forgive Sherlock without the threat of a bomb- and season 3 has yet to kick off._

 _Next time: Mrs Hudson meets the new addition to 221b, Sherlock avoids being bored and Harry gets some closure at Barts Hospital_


End file.
